1. Field Of The Invention
This invention generally relates to a mechanism which provides lifting and tilting for heavy containers, and more particularly to an elevatable cradle assembly which is adapted to turn gas cylinders such as propane or butane tanks.
2. Discussion Of Relevant Art
Numerous industries employ large containment vessels such as cryogenic fluids, propane, butane and other substances which, in most cases being volatile, are invariably contained within their containments in a liquid form under considerable pressure. Most of the containments have the general shape of cylinders, although in some cases cylindrical tanks, drums or barrels may be substituted with other shapes tending toward more cubical geometries. Irrespective of the containment type, withdrawal of the liquid contents is, in many cases, incomplete. In order to evacuate the remaining liquid contents or otherwise purge the containments, it has been found to be both expedient and economical to turn the containments, preferably by a 180.degree. degree turn or an inversion, and thereby drain the remaining liquid contents while the inherent volatility of the liquids serves to increase pressure in the containments, thus helping to expel the remaining liquid content.
The prior art of devices for tilting or inverting tanks, drums, barrels and the like includes containment characterized by modern pressurized, gas-containing cylinders such as are used for propane or butane storage. It should be understood, however, that such continual reference is by no means meant to limit the invention as to its utility for inverting containments of practically any geometry or size such as would be reasonably encountered in using the mechanism and apparatus hereinafter disclosed.
U.S. Pat. No. 2,670,864, a COMBINED HOIST AND POURING STAND FOR CONTAINERS discloses a container by envelopment within a cupping framework. Thereafter it is hoisted by lifting the framework between two vertical uprights of a footed stand by use of a conventional winch. The footed stand, or podium as I choose to term such mechanisms, is asymmetrical having parallel elongate members extending toward the front of his apparatus. Once the cupping frame is sufficiently elevated, the container which has been hoisted therein is tilted forward in a portion of the cupping frame that is pivotally mounted to the major elevational frame work.
Throughout the art there have myriad disclosures of tilting apparatus that range from garbage can tilters to barrel inverters. Recently, there has been effort expended to provide gas tank inversion apparatus. The Pro-Chem Company of Middlesex, N.J., catalogues a "Model CE-420 Tank Inverter" which is made to tilt and "invert" LP-GAS cylinders in order to enhance either product evacuation or facilitate repair or maintenance. Utilizing one person operation, it consists mainly in a base assembly comprising a podium (such as discussed above) having thereon two vertical, rigid supports which pivotally engage a cradle of size sufficient to handle the referenced LP-GAS cylinders (which may range up to 420 lbs). The CE-420 is, however, a ponderous mechanism acquired at considerable investment and which tilts or "inverts" a cylinder in an unconventional fashion. The cylinder is engaged in the cradle at the front of the podium and, while strapped to the cradle, is inverted, not by a simple pivotation, but by a lifting up and "over-the-shoulder" maneuver which actually moves the cylinder center of gravity in an arcuate motion beginning at the front of the podium and terminating, in the air, proximate the rear of the podium. That such a maneuver exacts a near-180.degree. inversion is not to be contested; however, it requires heavy duty framework, motive power, harness strengths and inherently unsafe maneuvering of the cylinder.